Formatters-only flavor

[withinfocus]

Is your feature request related to a problem? Please describe.

We desire a dual-use model of Mega-Linter as a pre-commit hook and a GitHub action, with the separation being formatters-only with the former and the entire suite with the latter. Put another way, we only want to address matters that are format-related locally, ideally with autofixing, to keep commits reasonably fast.

Describe the solution you'd like

A flavor that is only formatters -- and not overall linters -- to run with mega-linter-runner.

Describe alternatives you've considered

A combination of other settings, but we still have too much running locally that we'd like to defer to later.

[nvuillam]

The idea looks interesting :)

And as we have a is_formatter property on linter descriptors, it should be doable :)

cc @Kurt-von-Laven @bdovaz @echoix what do you think ?

[Kurt-von-Laven]

@withinfocus, are you already aware of the megalinter-incremental hook? We run it locally, and it's quite fast on a typical commit that doesn't touch every file in the repository, because it skips linters that run in project mode.

[withinfocus]

@Kurt-von-Laven yes indeed and that's what we have in place today, but it can still output results that are not formatting-related and potentially block a commit. We desire format-only to require success from Mega-Linter and allow potentially-subjective results from non-formatters to run later and not block commit (or even merge, such as during PR review).

[Kurt-von-Laven]

In that case, I can't think of a better solution than a formatter-only flavor.

[echoix]

I'd be interested in knowing for now, if the difference in image size would be worth building that additionnal flavor constantly, vs just deactivating the unneeded flavors. I expect that the set of linters change someday, but maybe we are quite close with what we have. Let's measure it with a proof of concept!

[withinfocus]

A flavor is one option but I thought that easier to implement than another configuration variable during invocation. If it's better for the product to have a FORMATTERS_ONLY or somesuch I think that's also very usable, but the cost then is a larger image utilization on each run and that seems more wasteful computationally.

[nvuillam]

We probably can handle both: a Formatters flavor + an option to run only formatters in any MegaLinter flavor, including the big one :)

[Kurt-von-Laven]

We could rename --filesonly to --files-only (keeping the original name as an alias for backwards compatibility), and add --formatters-only to mega-linter-runner?

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[withinfocus]

Still desired!

[nvuillam]

@withinfocus the backlog is big, and the available time is thin , you are right to post a reminder ;)

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity.
It will be closed in 14 days if no further activity occurs.
Thank you for your contributions.

If you think this issue should stay open, please remove the O: stale 🤖 label or comment on the issue.

[withinfocus]

Still desired!

[nvuillam]

@withinfocus it's on the way :)

[nvuillam]

@withinfocus the formatter flavor is available in beta :)

https://megalinter.io/beta/flavors/formatters/

[withinfocus]

Amazing! We'll try this out shortly.

[withinfocus]

This is successfully working in a private template repository. Anything we can help with to get this to leave beta? Testing was light but given the "is formatter" flag being the one real change used here it seems pretty safe to be considered stable.

[nvuillam]

@withinfocus it will be in the next minor release :)
Probably in the next 2 weeks ^^